The present invention generally relates to a water purification system and methods for providing potable water from contaminated water. More specifically, the present invention relates to a water purification system comprising a catalytic reactor, adsorbent and reverse osmosis units for providing potable water from water contaminated with chemical, biological, radiological and Toxic Industrial Chemicals (TICs) contaminants.
Water covers more than two-thirds of the Earth's surface. Nevertheless, there are many areas where water is scarce or where water, if available, is not potable and not suitable for human consumption. Obtaining sufficient quantities of potable water may be particularly problematic during military conflicts when it is necessary to provide potable water to troops in the field. During warfare, untreated water is potentially contaminated with a variety of toxic species, including chemical warfare agents such as sarin, mustard gas, phosgene, and cyanogens chloride. In addition, water may contain biological warfare agents such as anthrax or other biological toxins, including salmonella, hepatitis, small pox, and Norwalk virus and or radioactive agents. Water may also be contaminated with infectious agents emanating from poor local hygiene or sewage contamination as well as chemical pollutants from industrial and domestic sources. A water purification system that is both portable and highly efficient is desirable under such conditions.
Various water purification systems have been developed for purifying contaminated water, particularly water contaminated by chemical and/or biological warfare agents as well as radioactive agents. U.S. Pat. Nos. 4,699,720 and 6,423,236 both describe processes for water purification comprising catalytic thermal oxidation of chemical and/or biological warfare agents in the presence of an oxidizing agent and under high pressure and temperature. Reverse osmosis is used for further purification of water after the oxidation step. While these processes may be effective for providing potable water free of chemical and/or biological warfare agents, they are not effective for removal of radioactive agents. Reverse osmosis may provide 90-99% removal of radioactive agents, but this may not be sufficient to provide safe, potable water. Furthermore, any water purification system using these processes would have to provide both an oxidant for the catalytic thermal oxidation of chemical agents as well as the high temperatures and pressures required.
U.S. Published Application No. 2004/0168989 describes a system and method for water purification comprising non-thermal chemical oxidation where electrochemical generation of ozone is used to both oxidize chemical agents and kill biological agents. A major drawback to the system is that an additional unit is required to generate the ozone as well as subsequent removal of the ozone, in this case by UV irradiation. The system further comprises reverse osmosis and non-specific ion exchange for removal of radioactive agents. As with other systems in the prior art, there is some concern as to how effectively harmful radioactive agents are removed from the water.
As can be seen, there is a need for an efficient water purification system for removing chemical, biological and radioactive warfare agents from contaminated water to provide potable water. The water purification system should be highly efficient and portable. It would be desirable to have a system that is suitable for use during military conflicts.